Question 1

Which of the following best explains why mitochondrial DNA is useful for tracing maternal lineage in humans?

Accepted Answer

Mitochondrial DNA is inherited almost exclusively from the egg cell, so it reflects maternal ancestry.

Question 2

According to the endosymbiont theory, which cellular structure is believed to have originated from a photosynthetic prokaryote?

Accepted Answer

Chloroplast

Question 3

Which evidence supports the endosymbiont theory for the origin of mitochondria and chloroplasts?

Accepted Answer

Both organelles contain circular DNA and ribosomes similar to those of prokaryotes.

Question 4

A scientist discovers a cell with double-membraned organelles, circular DNA, and ribosomes similar to those in bacteria. Which process most likely led to the origin of these organelles?

Accepted Answer

Endosymbiosis of prokaryotic cells

Question 5

Which equation best represents the chemical reaction catalyzed by peroxisomes to detoxify hydrogen peroxide?

Accepted Answer

$$2 \mathrm{H}_2\mathrm{O}_2 \rightarrow 2 \mathrm{H}_2\mathrm{O} + \mathrm{O}_2$$

Question 6

Which of the following is NOT a function of the cytoskeleton in eukaryotic cells?

Accepted Answer

Synthesizing proteins

Question 7

Microtubules are essential for which of the following cellular processes?

Accepted Answer

Movement of cilia and flagella

Question 8

Which cytoskeletal element is primarily responsible for muscle contraction and cell crawling?

Accepted Answer

Microfilaments (actin filaments)

Question 9

A mutation disrupts the formation of intermediate filaments in a cell. Which cellular function is most likely to be affected?

Accepted Answer

Maintenance of cell shape and tension

Question 10

Which structure allows plant cells to communicate directly with each other by passing molecules through their cell walls?

Accepted Answer

Plasmodesmata

Question 11

Which component of the extracellular matrix (ECM) is primarily responsible for attaching animal cells to the ECM?

Accepted Answer

Integrins

Question 12

During the evolution of eukaryotes, which event occurred first according to the endosymbiont theory?

Accepted Answer

Formation of nuclear envelope

Question 13

Which of the following best describes the role of the central vacuole in plant cells?

Accepted Answer

It stores water and maintains cell turgor pressure.

Question 14

A cell is observed to have a high concentration of peroxisomes. Which function is this cell most likely specialized for?

Accepted Answer

Detoxification of alcohols and toxins

Question 15

Which of the following is a direct consequence of the double membrane structure of mitochondria?

Accepted Answer

It supports the endosymbiont theory, indicating an ancestral engulfing event.

Question 16

Which of the following best explains why mitochondria and chloroplasts have their own ribosomes and DNA?

Accepted Answer

They evolved from free-living prokaryotes that were engulfed by ancestral eukaryotic cells.

Question 17

Which of the following is a real-world application of understanding mitochondrial inheritance?

Accepted Answer

Tracing the maternal ancestry of human populations using mitochondrial DNA analysis.

Question 18

If a mutation occurs in the mitochondrial DNA, which type of inheritance pattern would you expect to see in the offspring?

Accepted Answer

Maternal inheritance

Question 19

Which of the following best describes the evolutionary advantage of compartmentalization in eukaryotic cells?

Accepted Answer

It allows for simultaneous and specialized biochemical reactions within different organelles.

Question 20

A researcher is studying a cell that lacks a Golgi apparatus. Which process would be most directly affected?

Accepted Answer

Modification and sorting of proteins for secretion

Mitochondria, Endosymbiont Theory, and the Evolution of Eukaryotic Cells

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